Why do I wake up with numbness on my little finger? Every morning

Ulnar nerve. A numb little finger is usually due to compression of the ulnar nerve. The most common place to compress it is at the elbow, sometimes by sleeping one your back with the elbow bent and the "funny bone" part of the elbow pressing against the bed. Another place to compress is at the wrist--usually by bending the wrist. If you sleep with your elbow bent a lot, there are ways to prevent that.